The normal, and presently widely used, high-lift systems for wings of civil and military aircraft comprise a multitude of high-lift flaps that are movably held on the wing and are driven by way of a transmission shaft train that extends into the wing, and by actuator devices arranged on said transmission shaft train. The embodiment comprising two actuator devices (also known as a “drive station”) for each high-lift flap to be moved is usual. The actuator devices are normally designed as linear spindle drives; with a corresponding design and redundant arrangement they can provide very high reliability. If nonetheless components of actuator devices or of the mechanical connections between actuator devices and high-lift flaps develop a malfunction during operation of the aircraft, blocking of an actuator device may occur. This subsequently results in blocking of the corresponding side of the high-lift flap to be moved, while the actuator device connected to the other side attempts to keep the other side moving. As a result of this the high-lift flap is subjected to torque until the torque produced by the still-intact actuator device is high enough to trigger a torque limiting means integrated in the actuator device, thus stopping operation of the central drive unit. Damage to, or detachment of, the high-lift flap can only be prevented by a corresponding damage-tolerant design, accompanied by the weight of the high-lift flap which consequently is not optimal.
A (high-lift) flap with devices for malfunction detection of the flap is disclosed in the printed publications EP 1 957 364 B1 and US 20090212977 A1, wherein the flap is connected to an evaluation device in order to switch off a central drive unit. The flap comprises a transmission element, for example a tube or a bar, arranged along the wingspan, wherein the transmission element carries a rigidly connected measuring arm in order to form a reference point that is connected to a sensor for detecting asymmetry or twisting of the flap.
In an alternative system a linear, flexurally soft sensor element is fed through high-lift flaps that are arranged side by side, on one end is affixed to a wing structure, and on the other end is attached to a linear sensor so that when the high-lift flaps are in an oblique position relative to each other one end of the sensor element and thus the linear sensor is pulled, which by means of a corresponding evaluation unit results in a signal that interrupts movement of the central drive unit.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.